block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO
Alternatively, this could use a "discard zeroes data" flag returned
by bdrv_get_info.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block.c b/block.c
index 97406ec..aa9ec83 100644
--- a/block.c
+++ b/block.c
@@ -3075,6 +3075,7 @@
{
int64_t length;
int64_t n;
+ int64_t ret;
length = bdrv_getlength(bs);
if (length < 0) {
@@ -3096,7 +3097,15 @@
return BDRV_BLOCK_DATA;
}
- return bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+ ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (!(ret & BDRV_BLOCK_DATA) && bdrv_has_zero_init(bs)) {
+ ret |= BDRV_BLOCK_ZERO;
+ }
+ return ret;
}
/* Coroutine wrapper for bdrv_get_block_status() */
